Oil burner



m1611946. D. C. ELUOT 'my 2,405,196

RNEYS Aug 5, 1946 D. c. ELLIOT` ETAL 2,405,196

' OIL BURNER Filed May 11, 1944 3 Sheets-Sheet 2 ATTO R N EYS 'Aug 61946- l." c. ELLIOT ETAI.- 2,405,196

OIL BURNER Filed May 11, 1944 s sheets-sheet s `mvE'N-romi .Zio/mw Eu/orAfm BY OFDM E PAW.

ATTORN EYS Patented Aug. 6, 1946 OIL BURNER` Donald C. Elliot, WestSpringfield, and Oreas H.

Paul, Chicopee, Mass., assignors to Gilbert & Barker ManufacturingCompany, West Springfield, Mass., a corporation of MassachusettsApplicaeonMay 11,1944, serial No. 535,034

(c1. s-1s) 3 Claims.

This invention relates to improvements in oil burners of the so-calledgun type adapted for residential heating purposes as distinguished fromindustrial furnaces.

More particularly, the invention is concerned with improvements havingto do with the manner in which the air is supplied to and mixed with aspray of atcmized oil issuing from a pressureatomizing nozzle. Ingeneral, the air is supplied in a stream, which whirls around and aroundthe conical oil spray, mixing therewith and burning with a relativelyshort flame. It is well known that if the air is supplied to the oilspray in a whirling manner, a more nearly perfect mixture of air and cilresult with better and more efficient combustion.

This invention has for an object to provide improved means for supplyingthe air to the oil spray in a whirling stream without turbulence andeffecting improved distribution of it around the oil spray so that theresulting mixture of oil and air is substantially uniform and the nameis of substantially uniform density throughout.

The invention has for another object to provide in a burner of the classdescribedan air tube of substantial length which is of circular crosssection and smooth from its inlet to its outlet end and to provide inthe inlet end of the tube a circular series of slots and a plenumchamber surrounding the slotted end of the tube together with means forforcing air into the plenum chamber and through said slots in a whirlingstream of substantially uniform thickness and advancing such streamwithout turbulence' to the outlet end of the air tube to envelop a sprayof oil issuing from a nozzle located in the tube at said outlet end.

The invention has for another object the provision in an arrangementsuch as has just been described, of slots which are helical with a steeppitch to assist in whirling the air and advancing it in the desiredhelical path.

The invention has for another object to combine with the slotted tube avalve sleeve movable on the tube to vary the effective area of the slotsthrough which air may enter the tube.

A further object of the invention is to provide in the air tube asupport for the oil nozzle andk The invention will be disclosed withreference to theV accompanying drawings, in which,

Fig. 1 is an elevational view, with parts in section and parts brokenaway, of an oil burner embodying the invention;

Fig. 2 is an end elevational View thereof;

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. 1;

f Fig. 4 is a sectional plan view taken on the line 1 -4 of Fig. 1;

Fig. 5 is a fragmentary cross sectional view taken on the line 5-5 ofFig. 1;

Fig. 6 is a fragmentary end view showing the cuter end of the air tubeas it appears when its end closure is swung open; and

Fig. 7 is a fragmentary view of the air valve showing a diierentmounting of the same.

Referring to these drawings and first to Figs. l and 4 thereof; theburner includes an air tube I, through which all of the air forcombustion is supplied to Ithe burner. This tube is of circular crosssection and usually it is of uniform diameter, thus being cylindrical asshown. However, the true cylindrical form is not necessarily essentialfor all purposes. The important characteristic is that the internalperipheral surface of the ltube is smooth from end to end so that air,which is whirled as it enters the tube at one end, may advance throughthe tube in a. whirling layer or stream, hugging its smooth wall, and

may issue from the tube in a whirling stream' without turbulence. Oneend of :tube I is closed, as by a plate 2. The other end is open butusually carries a more or less conical air nozzle 3 which condenses theair stream and directs it inwardly toward the oil spray.

Such spray is emitted from a pressure-atomizing nozzle 4 locatedcentrally of the tube, near its outlet end. This nozzle is carried by alongitudinally-disposed member 5, which forms a pari; of the oil supplyconduit for the nozzle. To the rear endof member 5 is connected a pipe 6which eX- tends rearwardly of the tube and outwardly therefrom, Vin amanner later to be described, for connectionY to an oil pump. Ignitionelectrodes 1 are also mounted in tube I with their spark gap located inoperative relation with nozzle A. Each electrode has a conductor `Ilwhich extends rearwardly of the tube and is supported by an insulatingtube 9. These'insulators' 9 and the member 5 are properly located withinthe tube I by a support, which includes a central massilll and aplurality (preferably three) of pin-like members II, for engaging theinner peripheral surface 'of the tube'. This mass I0 is streamlined,having 3 the curved surface I3', to guide any air, which may advance inthe central portion of the tube along the oil pipe 5, member orelectrode insulators 9, outwardly toward the peripheral part of the tubeto merge with the whirling stream. This guide insures that all the airin the tube is forced into the whirling.k peripheral layer which hugsthe wall of tube I. The streamlined guide also directs the air smoothlyas it leaves the pins and passes on toward the nozzle 4, preventing theeddies which might otherwise occur. The pins I i present very littleobstruction to the whirling air stream. Except for the pins I I, thereare no obstructions of a kind to create turbulence in the air stream.Very little turbulence is created by the not persist long enough to haveany effect on the air stream at the location where it acts on the oil ,A

spray.

The air is admitted to tube I through slots I2 which are formed in theperipheral' wall of the tube near its closed end.` Each slot extendsgenerally lengthwise ofthe tube and preferably is of the' helical formshown. The pitch V.of the helix may be right or left hand as desired.AThese slots are equally-spaced angularly around the tube in a circularseries. Rotatably mounted on the tube I, near its outer end, is asleev'eval've I3. Preferably, this sleeve has slots I3', Fig. 3, whichmatch the slots I2 and register therewith when the valve is in loneposition. The valve may be moved to various other positionsto partiallyclose slots I2 (see Fig. 3) and cut down the eiective area of theopenings through which air can enter tube I.

Air is fed into the described slots in a manner best shown in Fig. A fanI4 rotating in the direction of the arrow in a scroll chamber I5 forcesair through the conduit I6 into a plenum chamber Il. This chambercompletely surrounds the outer end of tube I and its only outlet is byway of slots I2 and I3 into tube I. The only inlet'to chamber I'I is byway of conduit I6, which is disposedv tangentially of the chamber,whereby the air entering the latter is caused to whirl around the tubeand to enter through the slots as indicated by the arrows and continueto whirl in tube I, advancing in a helica1 stream, hugging theperipheral wall of tube I,` to meet the oil spray.V

The helical form of theslots is preferred as this will assist in thewhirlingaction and in causing the air to travel forwardly in a helicalpath, as is desired. The valve may also be arranged as shown in pari; inFig. 7. With this arrangement the air enters the slots more smoothly andproduces a somewhat better whirling stream of air within the tube I. A Y

Referring now'more .particularly to the details of the exemplaryapparatus, the scroll chamber I5, conduit I6 and part of the plenumchamber Il are formed in a casting I8, which is supported vertically byan adjustable leg I9 from a base V23 as will be clear from Figs. 1 and'2. This casting has y a at end wall 2l from which projects the marginalflange 22 (Fig. 3) which denes thechambers I5 and I'I and theirconnecting conduit I6. A thin plate 23is secured to flange 22 with agasket 24 interposed between them,'as by a series of screws 25. Thisplate closes the scroll chamber recess in casting I8, except for aninlet 26, Fig. 1, opening axially ofrfan I4. It also closes the reberI'I. Fixed with this plate to the casting I8 is the end flangev of atube 21 which encompasses part of tube I in spaced relation therewith,'form-L.

.70.: cess in the Vcasting which forms'conduit I6 and' part of therecess which forms the plenum chaming an annular chamber which is partof the plenum chamber I'I, above described. This tube 21 is connected bya frusto-conical part 29 to a cylindrical sleeve 30 which closely tstube I and closes one end wa11 of the plenum chamber. The sleeve 30 isfastened as by welding, to tube l and serves to support the latter fromthe panel-like frame casting I8.

The sleeve valve I3, Fig. 4, extends from the closure plate 2 to thepart 29 and may be frictionally held in place between these parts. Thissleeve valve I3 has an annular ring 3| of angle section suitablyfastened thereto, as by welding. One face of this ring serves as aclosure for plenum vchamber I'I while the other seats in a circularopening in the wall of casting I8. The clo- Sure plate 2 (Fig. 2) islarge enough to close the last-named opening. This plate may abut theadjacent ends of tube I, sleeve valve I3 and ring 3l, as shown in Fig.4. The end plate 2 is hinged as at 32 to a support 33, Fig. 2, xed as byscrews 34 to a plate 35, which in turn is fastened by screws 38 to thecasting I8. When closed, plate 2 is held in place by a screw 37,threaded into casting I8.

For operating the sleeve valve I3, a handle 38 is provided. The innerend of this handle is fixed, as by welding, to the ring 3l of the valve(Fig, 6). The ange 39 is recessedat 40 to4k enable handle 38 to movethrough the range necessary to move I8 beneath plate 35. The hightensionterminalsI of the transformer are'shown at 4I and theirinsulators at 42. When the cover plate 2 is swung open to expose theouter end of the air tube, the terminals 4I of the transformer move awayfrom the ends of the conductors 8 and thus break the high tensioncircuit.

When closure`2 is open, the assembly'of nozzle 4, member 5, electrodes7, conductors 8, insulators 9, streamlined guide I0 and support pinsII,.may

be removed as a unit from tube I` by pulling out-v wardly on oil pipe 6after the latter has iirstbeen disconnected at the union-'43 `(Fig.Y 1).pipe, at the outer end of tube I ,extends radially outward through anotch 44 in tube IV (Figf) slots 45 and 4G in sleeve'valve" I3 and ring3|, respectively, and a notch 41 in flange 38. The slots 45 and 46enable the valve'I3 to turn through the desired range. notch 4l enters arecess 48,V Fig. 4,in wall 2U,

which lies beneath closure plate 2, and extends upwardly to the union43.'

An electric motor 49 islmounted on theframe i3 to drive the fanV I4 Aandan' oil pump. The Y motor casing is cylindrical and one end thereof liesin a circular opening 50 in the frame I8 but is spaced therefrom, Agutter 5I surrounds .part

of this opening 5B. The motor "has a series of' ears 52'Which Llie inthis gutter. Each ear has a' rubber Ybushing 53 therein and on eitherside of the ear are 'rubber' washers 54'. A steel 'plate 55l of arcuateform closes the gutter v5I and ieper-'- forated to'receive'screwsfonefor 'each ear.

Each screw passes throughplate4 55, and threadsv into the base'wallofthe guttei'gl The plate 553 The oil Y The cil pipe 6, on Vleaving'closely fits the outer and circular wall of gutter I but it does notengage the motor casing although it comes very close to it. The motor isthus resiliently supported from frame I3.

The motor has a single long bearing yEil for its shaft 58. The rotor isindicated at 5g and the stator at til, The fan iii is fixed to the oneend of shaft 58 which projects from the motor casing and it has its hubconnected to the fan by a conical part el, which enables the motorbearing to lie partly within it. A substantial part of the motor casinglies inside the frame, thereby materially lessening the part whichprojects outwardly from the frame. The motor casing houses in its outerend a fuel-supply unit which includes the pump, pressure-regulating andcut-off valves and iilter and may, for example, be constructed as shownin the application of Virgil E. Duemler, iiled April l, i944, underSerial No. 529,048, which application is owned by the assignee of thepresent application. For the present purposes, it will suiiice to statethat 62 indicates the pump, the outlet of which is suitably connected tothe pipe e, and 53 its drive shaft.

The oil pump is driven from the motor through a speed-responsivecoupling, comprising a drum Gli fixed to pump shaft t3, and a pair ofweight segments S5, pivotally mounted on pins t6 fixed to the rotor. Thecoupling is shown in more detail in Fig, 5. A spring el' connects a pint8 on each segment to the outer end of pivot pin 5E. Each segment has asuitable facing Sii to engage the inner periphery of the rim of drum da.It will be clear that as the motor reaches a certain speed. thecentrifugal force acting on the segments will overcome the force ofsprings 6l and swing the segments outwardly, pressing their facings t9against the drum and causing the latter and the pump shaft to rotate.The motor and fan are thus enabled to start up without the load of theoil pump and to acquire speed more rapidly than they wouid otherwise beable to do. Thus, the fan can have time to clear the dead air out oftube I and establish the desired whirling stream of air adjacent thenozzle before any oil issues from the nozzle. On deenergization of themotor, the coupling will soon operate to disconnect the pump, which willthen stop almost instantly, while the fan it. will continue in motiondue to its momentum and that of the heavy rotor 59. Thus, the emissionof oil from the nozzle d will be stopped before the air supply in orderto avoid poor combustion during the stopping interval of operation ofthe burner.

The frame i3 has a marginal flange 1I cf inverted U-shape to receive thecorrespondinglyshaped flange i2 on a cover 13. This cover has a slot Iof inverted U-form to f t over the tubular wall 2l. The cover isconnected near its upper end by a hook l5 on its inner wall engaging inan eye i6 on plate 23. The cover is further held in place by two screwsll', one adjacent each lower corner, which screws thread into the ange'I I.

ln operation, on energization of motor 19, the fan It is brought nearlyup to full speed before the speed-responsive coupling picks up the oilpump. The result is an establishment of substantially full air flow insufficient volume and at suflicient velocity to create the desiredwhirling air stream at and near the oil nozzle 4 before oil issuestherefrom in an atomized spray. lThis is an important improvement forthe reasons fully pointed out in the copending application of Warren H.DeLancey, filed May l, 1944, under Serial No. 535,036, which applicationis owned by the assignee of the present invention and in whichapplication said improvement is claimed.

According to the present invention, the air is admitted from the fan bypassage IE5 into plenum chamber I1 in a stream which enters the plenumchamber and is subdivided into a plurality of streams, one for each slotof the circular series. These air streams enter the slots, one througheach, and a much better distribution of the air eircularly is obtainedthan would be possible without it. Aside from uniform distribution oftheair, the slots of the preferred helical form assist in advancing the airin a spiral path through the tube. That is, air which enters any slot,as indicated in Fig. 1 by the arrow in the case of one slot, is free tomove forwardly (to the left as viewed in Fig. l) and the stream thus hasa tendency to move in a helical path as is desired. The several streamspassing through slots in tube I merge inside the tube in a single layeror stream of air which hugs the interior wall of the tube and advancesin a helical path to the nozzle of the burner. The stream issubstantially uniform in thickness due to the uniform feeding in of airthrough the slots at evenly distributed points around tube l. If any ofthe air flow lies inside the stream nearer the axis of tube I, thestreamined guide iE! will direct it outwardly and into the stream andwithout'creating turbulence. As the air passes the supporting pins I Iit has te be di- 'Vided to some extent but the obstructions offered bythese pins are so small as to be negligible. The air unites afterpassing the pins II and the uniform annular stream is guided to the oilspray by the cone 3 and by the forward streamlined part of guide Iii.The air issues from tube l, whirls around and around the oil spray,enveloping it, penetrating it and mixing with it. The mixture formed isexceptionally uniform as evidenced from observation of the resultingflame which shows uniform density throughout. A solid mass of flame ofuniform color throughout is obtained, indicative of a most effective anduniform mixing of the oil and air. These results are secured, it isbelieved, because the air when formed into a whirling stream at theinlet end of the air tube is uniformly distributed around the circularwall of the tube so that the air stream is of uniform thickness. Thenthe stream, so formed, is maintained in its formation while advancingalong the tube to meet the oil spray, by making the tube smooth from endto end to avoid turbulence such as would destroy the uniformdistribution of air in the stream. And the streamlined guide offers helpif and when needed by insuring that all air which passes it lies in thestream. The desired results are secured by a substantially uniformdistribution of air in the whirling envelope which surrounds the sprayand this, 0f course, results in a flame showing uniform density at allparts of it.

We claim:

1. In an oil burner, an air tube having an internal peripheral surfacewhich is smooth froml one end to the other, a closure for one end'of thetube, the other end of the tube being open and constituting the outletfor air for combustion, a pressure-atomizing nozzle mounted in theoutlet end of the tube and adapted to emit a conical spray of atomizedoil, said tube having in its periphery near its closed end and remotefrom said outlet a plurality of slots through which all the air forcombustion is admitted to said tube, said slots extending generallylengthwise of the tube and being angularly spaced about the periphery ofthe tube in a circular series; a housing having near its" lower end achamber enveloping the slottedvend of said tube, a scroll chamber nearits upper end and a conduit between said chambers; and a fan in saidscroll chamber, said conduit directing the air from the fan tangentiallyinto said lower chamber whereby the air whirls therein around theslotted portion of said tube enters the tube through said slots and isuniformly distributed around the tube and formed into a whirling streamwhich is advanced through said tube substantially Without turbulence tomix with the oil spray from said nozzle.

2. In an oil burner, an air tube having an internal peripheral surfacewhich is smooth from one end to the other, a closure for one end of thetube, the other end of the tube being open and constituting the outletfor air for combustion, a pressure-atomizing nozzle mounted in theoutlet end of the tube and adapted to emit a conical spray of atomizedoiLsaid tube having in'its periphery near its closed end and remote fromsaid outlet a plurality of slots through which all the air forcombustion is admitted to said tube, said slots being helical andangularly spaced about the periphery of the tube in a circular series; ahousing having near its lower end a chamber enveloping the slotted endof said tube, a scroll chamber near its upper end and a conduit betweensaid chambers; and a fan in said scroll chamber, said conduit directingthe air from the fan tangentially into said lower chamber whereby theair whirls therein around the slotted portion of said tube enters thetube through said slots and is uniformly distributed around the tube andformed into a whirling stream which is advanced through said tubesubstantially without turbulence to mix with the oil spray from saidnozzle.

3. In an oil burner, an air tube having an inte'rnal peripheral surfacewhich is smooth from one end to the other, a closure for one end of thetube, the other end of the tube being open and constituting the outletfor air for combustion, a pressure-atomizing nozzle mounted in theoutlet end of the tube and adapted to emit a conical spray of atomizedoil, said tube having in its periphery near its closed end and remotefrom said outlet a plurality of slots through which all the air forcombustion is admitted to said tube, said slots being helical andangularly spaced about the periphery of the tube in a circular series; ahousing having near its lower end a chamber enveloping the slotted endof said tube, a scroll chamber near its upper end and a conduit betweensaid chambers; and a fan in said scroll chamber, said conduit directingthe air from the fan tangen` tially into said lower chamber whereby theair whirls therein around the slotted portion of said tube enters thetube through said slots and is uniformly distributed around the tube andformed into a whirling stream which is advanced through said tubesubstantially without turbulence to mix with the oil spray from saidnozzle, a sleeve rotatably mounted on the tube and having helical slotsto match the slots in the tube and to register with the tube slots whenthe sleeve is in one position, said sleeve being movable on the tube tovary the effective area of the openings through which air enters saidtube.

DONALD C. ELLIOT.

OREAS H. PAUL.

